The phone cost vary on your what your status with T-mobile. If you can get a discount, the phone can be as cheap as $179 with a new 2 year contract. Without an contract or discount the phone sells strait up for $399.99.

The phone is a GSM based phone. With 3g data access as well as wifi.

The phone runs Android, the (Open handset alliance's/Google) new mobile OS. The Android part would be the same a Symbian (nokia), windows mobile (multiple handset makers) or Garnet (palm) etc... It is new, but 3rd party apps are being developed. Android is free and open source. based on a Linux kernel.